
Sour
Often Negative
Sour in taste often implies something is too acidic or maybe spoiled, suggesting a bad experience.
The soup has a sour flavor; I can't eat it.
Metaphorical Use
Sometimes 'sour' is used metaphorically to describe an experience that left a bad impression.
Losing the game left a sour taste in his mouth.
Intensity
Sour flavors range from slightly tart to intensely acidic; context helps clarify.
Limes are sour, but they're great in small amounts.